Detection of biological contamination protozoa in drinking water using surface plasmon resonance-based technique

Optical Review - Water is one of the fundamental needs for human life on earth. Different kinds of contaminants that exist in the drinking water may cause serious health issues, affect body organs,...     

Impact of Top Electrodes (Cu,Ag, and Al) on Resistive Switching behaviour of Cu-rich Cu2ZnSnS4 (CZTS) Ideal Kesterite

Cu₂ZnSnS₄ (CZTS) active material-based resistive random-access memory (RRAM) devices are investigated to understand the impact of three different Cu, Ag, and Al top electrodes. The dual resistance switching (RS) behaviour of spin coated CZTS on ITO/Glass is investigated up to 10² cycles. The stability of all the devices (Cu/CZTS/ITO, Ag/CZTS/ITO, and Al/CZTS/ITO) is investigated up to 10³ sec in low- (LRS) and high- (HRS) resistance states at 0.2 V read voltage. The endurance up to 10² cycles with 30 msec switching width shows stable write and erase current. Weibull cumulative distribution plots suggest that Ag top electrode is relatively more stable for set and reset state with 33.61 and 25.02 shape factors, respectively. The charge carrier transportation is explained by double logarithmic plots, Schottky emission plots, and band diagrams, substantiating that at lower applied electric field intrinsic copper ions dominate in Cu/CZTS/ITO, whereas, at higher electric filed, top electrodes (Cu and Ag) dominate over intrinsic copper ions. Intrinsic Cu⁺ in CZTS plays a decisive role in resistive switching with Al electrode. Further, the impedance spectroscopy measurements suggest that Cu⁺ and Ag⁺ diffusion is the main source for the resistive switching with Cu and Ag electrodes.     

Recent Advances On Direct Formylation Reactions

Aldehydes serve as the key functional group in organic synthesis and are valuable intermediates. The various advanced methods of direct formylation reactions have been reviewed in this article. Overcoming the drawbacks of the traditional methods of formylation, newer methods involving homo and heterogenous catalysts, one pot reactions, solvent free techniques are elaborated, which can be performed under mild conditions and using inexpensive resources.     

A Novel Electroanalytical Biosensor Based on ZIF-8/Acetylcholinesterase Bio-nanohybrids for Early Management of Hirschsprung Disease

Hirschsprung's disease (HD) is characterised by missing nerve cells in the colon of infants and children which results in strained bowel movement. Under such situations, undiagnosed and untreated cases often lead to a cascade of gastrointestinal infections eventually resulting in Hirschsprung-assisted enterocolitis which has significantly high mortality rate. This is further exacerbated by the absence of suitable, sensitive and efficient technologies to detect the pathological segment of the intestine, which could significantly reduce surgery duration in the operation theatre, as well as associated risks to patients. It therefore becomes a matter of extreme importance to develop a point-of-care platform for early and efficient management/identification of the occurrence of HD in neonates and older children during its onset, before it proves fatal with life-threatening outcomes. The present work reports an electrochemical enzymatic biosensor using Zeolitic Imidazolate Framework-8 (ZIF-8) modified with acetylcholinesterase enzyme (AchE), for detection of HD as a function of the key biomarker – acetylcholine. The developed sensor was initially characterized using Cyclic Voltammetry (CV) and Electrochemical Impedance Spectroscopy (EIS), while the analytical performance and insights onto interfacial redox kinetics were assessed using Differential Pulse Voltammetry (DPV) and EIS respectively. The sensor exhibited limit of detection and sensitivity of 0.19 μM and sensitivity of 0.42 μA/μM/mm² with a shelf life of 1 month, while remaining unperturbed in the presence of common interferants. The performance of developed sensor was also examined in spiked serum samples and was observed to yield a high degree of linearity.